Architects and the public at large appreciate the aesthetics of glass and other light transmitting materials used in the built environment. Light transmitting materials that serve both an aesthetic function as well as a structural function are appreciated for their economy and visual effects. A common means prescribed by architects to achieve these goals in building structures is through the use of glass “curtain wall” systems.
Conventional curtain walls cover an outer surface of a building in a non-structural manner. The non-structural curtain wall is usually made of lightweight material to reduce loads and construction costs. Conventional curtain walls are often designed with extruded aluminum members and the aluminum members are infilled with glass or other members. Glass curtain walls can be advantageous since they allow natural light to penetrate into the building. The curtain wall structure usually will not bear any load from the building except for the weight of the curtain wall itself, and the wall transfers wind loads incident upon the curtain wall surface to the main building structure through connections at floors or columns of the building.
Aesthetic design and performance levels of curtain walls can be extremely varied. Frame system widths, depths, anchoring methods, and accessories have grown diverse due to industry and design innovation. Two common categories are “pressure wall” and “structurally glazed” systems. A pressure wall system utilizes an exposed pressure plate to retain the glass on the face of the supporting frame, whereas a structurally glazed design has no such exposed fastener.
Although some glass and frame technologies have been developed that are capable of passing applicable fire test and building code requirements, no such system has been developed for structurally glazed curtain wall systems, which have no exposed pressure plates or fasteners that retain the exterior glass. Accordingly, there is a need for a structurally glazed system that is capable of meeting or exceeding existing fire test and building code requirements.